This invention relates to a chewing gum product with a hard coating thereon, and in particular to sugarless chewing gum products with a hard coating comprising erythritol, and methods of making such products.
Chewing gums, including pellet chewing gums, are frequently enclosed with hard or soft coatings. Coatings provide an opportunity for the manufacturer to vary product characteristics such as taste, appearance and nutritional value. In recent years, efforts have been devoted to producing sugarless hard coatings for use in chewing gum. Sugarless coatings which have been investigated include coatings containing compounds such as xylitol, sorbitol, mannitol and hydrogenated starch hydrolysates.
Erythritol has been proposed for use as a chewing gum ingredient. U.S. Pat. No. 5,120,550 discloses a chewing gum made with a sweetening agent containing erythritol and a liquid sugar alcohol.
Low calorie sweetening compositions containing meso-erythritol are disclosed in U.S. Pat. No. 5,080,916 and U.S. Pat. No. 4,902,525, EPO Patent Publication No. 0 325 790, and Japanese Patent Publications No. 89-225458 and No. 90-104259.
Japanese Patent No. 89-51045 discloses chewing gum made with a melted mixture of meso-erythritol and sugars or sugar alcohols.
EPO Patent Publication No. 0 497 439 discloses a sweetener employing the use of spray dried erythritol.
U.S. Pat. No. 5,273,771 and EPO Patent Publication No. 0 511 761 disclose a sweetening composition made up of erythritol, sorbitol, and a glucose oligomer.
PCT Publication No. W093/00828 discloses a stabilized dipeptide sweetening composition which is useful in chewing gum and may contain erythritol.
Other patents and publications which discuss erythritol include U.S. Pat. No. 4,382,963 and U.S. Pat. No. 5,156,866 (erythritol used in chewing gum); Japanese Patent Publications No. 92-287658 and No. 92-287659, both published Oct. 13, 1992, (sweetening compositions containing meso-erythritol); Japanese Patent Publication No. 93-137535 published Jun. 1, 1993, (free flowing sweetener containing erythritol) and European Patent Publication No. 0 530 995, published Mar. 10, 1993, (lozenge containing sweetener which is all or partly erythritol or maltitol).
EPO Patent Publication No. 0 009 325 and Japanese Patent Publication No. 81-18180 disclose a method of reducing dental caries with a sugarless chewing gum made with erythritol. Example VIII of these equivalent EPO and Japanese applications dust the example chewing gum composition with erythritol powder.
Sugarless xylitol coated pellet gums have become very popular and products are being manufactured in Europe and Canada. Coating with xylitol is described in U.S. Pat. No. 4,105,801, issued Aug. 8, 1978, to Dogliotti; U.S. Pat. No. 4,127,677, issued Nov. 28, 1978, to Fronczowski et al.; U.S. Pat. No. 4,681,766, issued Jul. 21, 1987 and U.S. Pat. No. 4,786,511, issued Nov. 22, 1988, to Huzinec et al.; and U.S. Pat. No. 4,828,845, issued May 9, 1989, to Zamudio-Tena et al.
The most common and lowest costing polyol used in chewing gum is sorbitol. However, panning with sorbitol has been very difficult since it is hygroscopic and does not readily crystallize. A number of patents have been published that use various procedures to coat with sorbitol, including U.K. Patent No. 2,115,672; U.S. Pat. No. 4,317,838; and U.S. Pat. No. 4,753,790. A successful sorbitol hard coating was reported in U.S. Pat. No. 4,423,086, particularly when the sorbitol was at least 99% D-sorbitol. However, the quality of coating never approached the quality of typical xylitol hard coatings.
Another coating patent, U.S. Pat. No. 4,840,797, discloses the use of maltitol in a coating. Again, a high purity in the maltitol (over 95%) was required in order to obtain a good quality coating on pellet gum. Also hydrogenated isomaltulose is disclosed as a coating material in U.S. Pat. Nos. 5,248,508 and 4,792,453.
In order to obtain coatings of lower cost, some of the xylitol is replaced by sorbitol, lactitol, or maltitol. However, these cannot be applied in the same solution, but must be applied by alternating solutions. In other words, a solution of one polyol is applied, then another solution of another polyol is applied. This is disclosed in U.S. Pat. No. 5,270,061. See also PCT Applications Serial Nos. PCT/US93/09354 (published as WO 95/08925) and PCT/US93/08730 (published as WO 95/07622), both of which are hereby incorporated by reference.
Thus far it has proven difficult to mix crystallizable polyols in a single coating solution to obtain a quality sugarless coating. A booklet entitled "The Evaluation of Chewing Gum--Xylitol and the Prevention of Dental Caries" published in 1985 by Xyrofin describes a coating formed by panning containing xylitol and up to 10% sorbitol. However, it has been difficult in practice to use more than 5% sorbitol in a xylitol panning coating, and at these low levels, the sorbitol acts as a crystallization modifier.
In an approach different from panning from a solution, U.S. Pat. No. 4,146,653 discloses a molten blend of xylitol and sorbitol that are used to form a coating.
The cost of xylitol is quite high, and replacement of the xylitol in the coating would be an advantage. There is a need for a less expensive sugarless coating for chewing gum, especially one that produces a smoother coating, dries easier and is less hygroscopic than other sugarless coatings.